Device and method for testing ionic conductivity in thin film Through-Plane direction

Abstract

The invention belongs to the field of film testing, and discloses a device and a method for testing the ionic conductivity of a film in the Through-Plane direction, the device comprises a base and a testing device, a vertical support frame on the base is provided with a distance adjusting device capable of sliding up and down so as to accurately adjust a film clamping gap, the testing device is divided into a first testing unit and a second testing unit, a contact electrode and a built-in field adjusting device are respectively configured and are used for accessing and adjusting an electric field, a magnetic field or a thermal field. According to the integrated design, the operation process is remarkably simplified, dependence on skills of personnel is reduced, the testing precision is greatly improved, the application range is greatly widened through precise external field control and direction adaptability, the device can efficiently meet the actual working condition characterization requirements of different types of thin film materials, and the device is suitable for large-scale popularization and application. Finally, the defects in the aspects of external field integration, test direction matching and multifunctional cooperation in the prior art are overcome.

Description

Technical Field

[0001] This invention belongs to the field of thin film testing technology, and particularly relates to a device and method for testing the through-plane ionic conductivity of thin films. Background Technology

[0002] With the rapid development of new energy technologies, technological innovations in core areas such as fuel cells and lithium-ion batteries are advancing at an unprecedented pace. This trend places increasingly stringent demands on the performance of key supporting materials—thin-film materials. As a core component in energy storage and conversion devices, thin-film materials play a crucial role in ion transport, and their ion conductivity directly determines the energy efficiency and operational stability of the entire device. Among these, the through-plane ion conductivity of thin-film materials is one of the core indicators for accurately measuring their suitability and application value. It is directly related to key performance parameters such as charge / discharge rates and cycle life of batteries and other devices, and therefore has received widespread attention and high regard within the industry.

[0003] However, current mainstream thin-film ionic conductivity testing devices still have many shortcomings that urgently need to be addressed. From an operational perspective, existing devices are generally cumbersome, requiring high levels of operator skill, which hinders efficient testing. In terms of performance, their accuracy is insufficient, failing to meet the demands of high-precision characterization, and their applicability is limited, unable to adapt to testing scenarios for different types and specifications of thin-film materials. Regarding functional integration, their level of external field integration is low, making it difficult to collaborate with other testing systems to achieve multi-dimensional performance characterization. More importantly, most existing devices focus on testing the in-plane ionic conductivity of thin films, while in practical applications such as fuel cells and lithium-ion batteries, thin films mostly operate in the through-plane direction. Especially for anisotropic thin-film materials, the ionic conductivity in the through-plane direction differs significantly from that in the in-plane direction, and existing testing devices clearly cannot meet the testing direction requirements of practical applications.

[0004] It is evident that existing thin film ion conductivity testing devices are insufficient to accurately characterize the ion conductivity performance of thin films under actual operating conditions, thus failing to meet the ever-increasing testing demands. Summary of the Invention

[0005] This invention provides a testing device and method for the through-plane ionic conductivity of thin films. Using this testing device can effectively solve the problem that existing thin film ionic conductivity testing devices are difficult to accurately characterize the ionic conductivity performance of thin films under actual working conditions, thereby meeting the growing testing needs.

[0006] To achieve the above objectives, the present invention employs the following technical content: A device for testing the through-plane ionic conductivity of thin films, comprising: a base and a testing device; The base is vertically equipped with a support frame; The support frame is equipped with an adjustment device that can slide up and down in the vertical direction. The adjustment device is used to finely adjust the clamping gap of the film to be tested. The testing device includes a first testing unit and a second testing unit; The first test unit is located at the bottom of the adjustment device; The second test unit is disposed on the top surface of the base; Both the first test unit and the second test unit are provided with contact electrodes for contacting the thin film under test; Both the first test unit and the second test unit have cavities; field adjustment devices are respectively inserted into the cavities, and the field adjustment devices are used to connect to and adjust different electric fields, magnetic fields or thermal fields.

[0007] Furthermore, the support frame is provided with slide rails; The adjusting device is movably connected to the slide rail via a connecting device.

[0008] Furthermore, the connecting device includes a horizontally arranged fixing plate; the fixing plate is connected to the slide rail by fastening screws; The adjusting device includes a connected size adjusting component and a fixing component; The top of the fastener is connected to the size adjustment component, the middle part is connected to the fixing plate, and the bottom part is connected to the first test unit.

[0009] Furthermore, the support frame is provided with a scale, and the fastening screw can indicate the adjustment scale position to realize the coarse adjustment of the testing device; wherein, the adjustment range of the coarse adjustment is 0 cm to 20 cm; The size adjustment component is equipped with a micrometer, vernier caliper, or electronic ruler to achieve fine adjustment of the testing device; wherein the adjustment range of the fine adjustment distance is 0 mm to 20 mm, and the adjustment accuracy is 1 μm.

[0010] Furthermore, the cavity is coated with a thermally conductive and insulating material; the thermally conductive and insulating material is a ceramic material, hexagonal boron nitride, or a polymer material. The contact electrode is made of a metallic electrode material or a two-dimensional material.

[0011] Furthermore, the field adjustment device is connected to a DC regulated power supply and a voltage divider circuit to adjust the electric field, with an adjustment range of 0.01 V / cm to 10 V / cm; Alternatively, the field adjustment device is connected to an electromagnet and a current adjustment module to adjust the magnetic field, with an adjustment range of 0 mT to 200 mT; Alternatively, the field adjustment device is connected to a semiconductor temperature control module and a platinum resistance temperature measurement feedback adjustment module to adjust the thermal field, with an adjustment range of -40 ℃ to 200 ℃.

[0012] Furthermore, among which: When the field adjustment device is connected to the electric field, the field adjustment device is made of platinum-iridium alloy and its surface is coated with a titanium nitride conductive layer. When the field adjustment device is connected to the magnetic field, the field adjustment device uses a neodymium iron boron permanent magnet, with an outer layer wrapped with a silicon steel sheet magnetic shielding layer; When the field conditioning device is connected to the thermal field, the field conditioning device adopts a composite structure of aluminum nitride ceramic substrate and nickel-chromium heating element, and the surface of the ceramic substrate is covered with a polytetrafluoroethylene heat insulation layer.

[0013] A method for testing the through-plane ionic conductivity of thin films, based on the aforementioned device for testing the through-plane ionic conductivity of thin films, comprising: The pretreated film to be tested is placed on the second test unit; The first test unit is moved downward by the adjusting device until the contact electrodes of the first and second test units are in contact with the film under test. By adjusting the spacing device, the distance between the first test unit and the second test unit is finely adjusted with micron-level precision until the current thickness of the film under test is ≤ ±1 μm from the initial thickness. The parameters of the field conditioning device are set according to the test requirements to connect to and adjust different electric fields, magnetic fields or thermal fields to construct the field environment; Under the current field conditions, electrochemical impedance signals are collected, and the ionic conductivity of the thin film in the through-plane direction is calculated based on the electrochemical impedance signals.

[0014] Furthermore, the pretreatment process for the thin film to be tested includes: The thickness of the thin film under test is measured in multiple uniformly distributed areas using a micrometer with micron-level precision, and the average value is taken as the initial thickness. The film to be tested is cut into a shape that matches the contact electrode; If the membrane to be tested is an electrolyte membrane, the electrolyte membrane shall be dried in advance.

[0015] Further, the step of acquiring electrochemical impedance signals under the current field environment and calculating the through-plane ionic conductivity of the thin film based on the electrochemical impedance signals includes: Acquire electrochemical impedance signals within a preset frequency range; Nyquist plots are generated based on electrochemical impedance signals; The Nyquist plot was fitted with an equivalent circuit to extract the bulk resistance of the thin film in the through-plane direction. Combined with the contact resistance obtained from the blank experiment, the actual bulk resistance of the thin film was calculated. Based on the actual thin film bulk resistance, the thin film thickness during the test process, and the effective area of ​​the contact electrode, the through-plane ionic conductivity of the thin film is calculated according to the ionic conductivity formula.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a testing device for the through-plane ionic conductivity of thin films, comprising a base and a testing device. A vertical support frame on the base is equipped with a sliding adjustment device to precisely adjust the film clamping gap. The testing device is divided into first and second testing units, each equipped with contact electrodes and a built-in field adjustment device for connecting and controlling electric, magnetic, or thermal fields. The adjustment device ensures the film is firmly fixed in the through-plane direction, avoiding the limitations of traditional devices that only focus on the in-plane direction. Simultaneously, the field adjustment device allows for the simulation of multi-dimensional external field conditions in real-world applications, thereby directly deriving the film's ionic conductivity performance in this direction. This integrated design significantly simplifies the operation process, reduces reliance on human skills, and greatly improves testing accuracy and applicability through precise external field control and directional adaptability. The device can efficiently meet the characterization needs of different types of thin film materials under actual working conditions, ultimately overcoming the shortcomings of existing technologies in external field integration, testing direction matching, and multi-functional synergy. This invention also provides a method for testing the through-plane ionic conductivity of thin films. Based on the aforementioned testing device for through-plane ionic conductivity of thin films, this method first places the pretreated thin film to be tested on a second testing unit. A distance adjustment device drives the first testing unit downwards until the contact electrode just contacts the film. Then, the clamping gap is precisely adjusted with micrometer-level precision to ensure film thickness stability. Simultaneously, a field adjustment device is used to connect and control the electric, magnetic, or thermal fields to construct a multi-dimensional external field environment simulating actual working conditions. By precisely controlling the fixed state of the film in the through-plane direction and the external field parameters, the acquisition of the electrochemical impedance signal directly corresponds to the ion transport behavior in this direction, thereby deriving the accurate ionic conductivity. This method significantly simplifies the operation process, reduces reliance on professional skills, improves testing accuracy and applicability, and can flexibly integrate multiple external fields to achieve multi-dimensional collaborative characterization. It effectively solves the problems of test direction mismatch, low external field integration, and cumbersome operation in existing technologies, meeting the needs of high-performance thin film material characterization in practical applications. Attached Figure Description

[0017] Figure 1 A schematic diagram of a device for testing the through-plane ionic conductivity of a thin film provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the testing principle of the testing device provided in the embodiment of the present invention; Figure 3 Impedance spectrum of a 10 μm film measured using this device (compression ratio too high, 50%), provided for embodiments of the present invention. Figure 4 Impedance spectrum of a 10 μm film measured using this device (moderate compression, 2-5%) is provided for embodiments of the present invention. Figure 5 Impedance spectrum of a 10 μm film measured using this device (compression ratio insufficient, 0%) provided for embodiments of the present invention. Figure 6 The impedance spectrum of a 1 cm gel was measured using this device (compression ratio too high, 50%), as provided in this embodiment of the invention. Figure 7 Impedance spectroscopy of a 1 cm gel (with moderate compression, 2-5%) based on this device is provided for embodiments of the present invention. Figure 8 Impedance spectrum of 1 cm gel measured using this device (compression ratio less than 0%), provided for embodiments of the present invention. Figure 9 The impedance spectrum of a 60 μm film measured under an electric field using this device is provided for embodiments of the present invention (moderate compression, 2-5%, electric field strength 0.5 V / cm). Figure 10 Impedance spectrum of a 60 μm film measured under a magnetic field using this device (moderate compression, 2-5%, magnetic field strength 20 mT) is provided for embodiments of the present invention. Figure 11 The impedance spectrum of a 60 μm film measured under a thermal field using this device is provided for embodiments of the present invention (moderate compression ratio, 2-5%, temperature 60 °C).

[0018] Figure label: 1. Base; 2. Support frame; 3. Slide rail; 4. Connecting device; 5. Testing device; 6. Adjustment device; 7. Field adjustment device; 8. Contact electrode; 9. Thin film to be tested; 4-1. Fixing plate; 4-2. Fastening screws; 5-1, First Test Unit; 5-2, Second Test Unit; 6-1. Size adjustment parts; 6-2. Fixing parts. Detailed Implementation

[0019] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] The technical terms involved in this invention will be explained below: Through-Plane describes a direction in space that is perpendicular to a plane.

[0024] A Nyquist plot is a frequency response diagram drawn on the complex plane. It visually reflects the dynamic characteristics of a system or component by showing the trajectory of its impedance (or transfer function) as frequency changes.

[0025] As mentioned in the background section, existing thin film ionic conductivity testing devices have several shortcomings: complex testing processes, insufficient testing accuracy, limited applicability, and low integration with the external field. Furthermore, most devices only test the ionic conductivity in the in-plane direction. However, in practical applications, thin films mostly operate through-plane conditions. For anisotropic thin films, the ionic conductivity in the through-plane direction differs significantly from that in the in-plane direction.

[0026] To address the aforementioned issues, this embodiment provides a testing device for the through-plane ionic conductivity of thin films. This testing device couples a high-precision micrometer to a thin film clamping structure as an adjustment device for the clamping gap, enabling adjustment of the clamping gap in 1 μm increments. This testing device features integrated structure and high testing accuracy.

[0027] like Figure 1 As shown, this embodiment provides a testing device for the through-plane ionic conductivity of thin films, including a base 1, a support frame 2, a slide rail 3, a connecting device 4, a testing device 5, a spacing adjustment device 6, and a field adjustment device 7, wherein: A support frame 2 is vertically mounted on the base 1, and a slide rail 3 is mounted on the top of the support frame 2. The slide rail 3 is equipped with an adjustment device 6 and is fixed by a connecting device 4. The test device 5 is divided into two parts, namely the first test unit 5-1 and the second test unit 5-2. The contact part between the test device 5 and the film 9 to be tested is equipped with a conduction system. A field adjustment device 7 is provided between the base 1 and the adjustment device 6. The field adjustment device 7 can adjust different electric fields, magnetic fields and thermal fields according to the test requirements.

[0028] For example, the connecting device 4 includes a fixing plate 4-1 and a fastening screw 4-2; wherein, the fixing plate 4-1 is horizontally arranged and is slidably fixed on the slide rail 3 by the fastening screw 4-2; by adjusting the fastening screw 4-2, the fixing plate 4-1 drives the adjusting device 6 to move up and down, thereby adjusting the gap distance between the two parts of the testing device 5; wherein, the adjusting device 6 includes a connected size adjusting component 6-1 and a fixing component 6-2; the size adjusting component 6-1 and the fixing component 6-2 can be connected by welding, threaded connection or integral molding; the size adjusting component 6-1 serves as a fine adjustment device; the middle part of the fixing component 6-2 is connected to the center threaded hole of the fixing plate 4-1 by a built-in bolt, and the bottom passes through the fixing plate 4-1 and is connected to the first testing unit 5-1 of the testing device 5.

[0029] For example, the adjusting device 6 also includes a coarse adjusting device, which is implemented by the slide rail 3 and the fastening screw 4-2 (or gear); the fine adjusting device is implemented by one of a micrometer, vernier caliper or electronic ruler.

[0030] As a preferred embodiment, a scale is provided on the support frame 2, and the fastening screw 4-2 (or gear) can indicate the adjustment scale position to complete the coarse adjustment between the first test unit 5-1 and the second test unit 5-2, with an adjustment range of 0 cm to 20 cm; with the help of a micrometer, vernier caliper or electronic ruler, the fine adjustment between the first test unit 5-1 and the second test unit 5-2 can be achieved; wherein, the adjustment range of the fine adjustment distance is 0 mm to 20 mm, and the adjustment accuracy is 1 μm.

[0031] In this embodiment, the testing device 5 is divided into two parts, namely the first testing unit 5-1 and the second testing unit 5-2, and both parts are provided with cavities to accommodate the field adjustment device 7.

[0032] For example, the field adjustment device 7 can adjust one or more combinations of electric field, magnetic field, and thermal field.

[0033] For example, both the bottom surfaces of the first test unit 5-1 and the second test unit 5-2 are provided with contact electrodes 8 for forming electrical contact with the thin film 9 under test for testing. The contact electrodes 8 are made of metal electrode materials (such as copper, silver, gold, platinum, stainless steel, etc.) or two-dimensional materials (graphene oxide, molybdenum disulfide, etc.). The contact electrodes 8 are also connected to wires for connecting to an external electric field, magnetic field, and thermal field, or any combination thereof.

[0034] In this embodiment, the cavity is coated with a thermally conductive and insulating material; the thermally conductive and insulating material is a ceramic material, hexagonal boron nitride (h-BN), or a polymer material. Specifically, the ceramic material may be alumina ceramic, aluminum nitride ceramic, etc.; the polymer material may be thermally conductive silicone, thermally conductive epoxy resin, or thermally conductive rubber.

[0035] In this embodiment, the field adjustment device 7 is connected to a DC regulated power supply and a voltage divider circuit to adjust the electric field, with an adjustment range of 0.01 V / cm to 10 V / cm. Alternatively, the field adjustment device 7 is connected to an electromagnet and a current adjustment module to adjust the magnetic field, with an adjustment range of 0 mT to 200 mT; Alternatively, the field adjustment device 7 is connected to the semiconductor temperature control module and the platinum resistance temperature measurement feedback adjustment module to adjust the thermal field, with an adjustment range of -40 ℃ to 200 ℃.

[0036] Explainable, of which: When the field conditioning device 7 is connected to the electric field, the field conditioning device 7 is made of platinum-iridium alloy and the surface is coated with a titanium nitride conductive layer. When the field adjustment device 7 is connected to the magnetic field, the field adjustment device 7 uses neodymium iron boron permanent magnets, and the outer layer is wrapped with a silicon steel sheet magnetic shielding layer; When the field conditioning device 7 is connected to the hot field, the field conditioning device 7 adopts a composite structure of aluminum nitride ceramic substrate and nickel-chromium heating element, and the surface of the ceramic substrate is covered with polytetrafluoroethylene heat insulation layer.

[0037] like Figure 2 As shown, based on the above-described testing apparatus, this embodiment also provides a method for testing the through-plane ionic conductivity of thin films, including: The pretreated test film 9 is placed on the second test unit 5-2; The adjusting device 6 drives the first test unit 5-1 to move downward until the contact electrodes 8 of the first test unit 5-1 and the second test unit 5-2 form a just contact state with the film 9 to be tested. By adjusting the spacing device 6, the distance between the first test unit 5-1 and the second test unit 5-2 is finely adjusted with micron-level precision until the current thickness of the film 9 to be tested deviates from the initial thickness by ≤ ±1 μm. The parameters of the field conditioning device 7 are set according to the test requirements to connect to and adjust different electric fields, magnetic fields or thermal fields to construct the field environment; Under the current field conditions, electrochemical impedance signals are collected, and the ionic conductivity of the thin film in the through-plane direction is calculated based on the electrochemical impedance signals.

[0038] As a preferred embodiment, the pretreatment process of the thin film 9 to be tested includes: The thickness of the film 9 under test was measured in multiple uniformly distributed areas using a micrometer with micron-level precision, and the average value was taken as the initial thickness. The film 9 to be tested is cut into a shape that matches the contact electrode 8; If the membrane to be tested 9 is an electrolyte membrane, the electrolyte membrane shall be pre-dried.

[0039] In this process, under the current field environment, electrochemical impedance signals are collected, and the through-plane ionic conductivity of the thin film is calculated based on the electrochemical impedance signals. Specific steps include: Acquire electrochemical impedance signals within a preset frequency range; Nyquist plots are generated based on electrochemical impedance signals; The Nyquist plot is fitted with an equivalent circuit to extract the bulk resistance of the thin film in the through-plane direction. Combined with the contact resistance obtained from the blank experiment, the actual bulk resistance of the thin film is calculated. Based on the actual thin film bulk resistance, the thin film thickness during the test process, and the effective area of ​​the contact electrode, the through-plane ionic conductivity of the thin film is calculated according to the ionic conductivity formula.

[0040] In this embodiment, the testing method is further explained: the specific operation steps are as follows: 1. Preparation before testing and sample pretreatment: 1.1 Basic Equipment Inspection: Start the main control system of the test equipment, check the smoothness of the movement of the adjusting device along the slide rail without jamming or deviation, set the output function of the electric field / magnetic field / thermal field of the field adjustment device 7 to zero field state, and confirm that there is no abnormal field strength output. Wipe the surface of the contact electrode with a lint-free cloth to remove oxide layer or impurities to avoid affecting the impedance signal and the connection stability of the conduction system with the electrochemical workstation to ensure that the impedance signal can be transmitted normally. At the same time, start the electrochemical workstation and perform self-testing, such as open circuit voltage calibration and impedance range calibration, to ensure that the equipment is in normal working condition.

[0041] 1.2 Thin Film Sample Processing and Fixation: Select 9 thin film samples to be tested, and measure the thickness in 5 evenly distributed areas of the sample using a micrometer with an accuracy of 1 μm. Record the average value as the initial thickness. Cut the sample to a shape with a shape error of ≤ ±0.5 mm that matches the size of the contact electrode to prevent the sample edge from exceeding the electrode and causing uneven impedance distribution. If the sample is an electrolyte film, it needs to be dried in a vacuum drying oven in advance, such as drying at 60 ℃ for 12 h, to remove the internal moisture of the sample and avoid moisture affecting ion conduction. After drying, place the sample in the center of the contact electrode 8 of the lower part of the test device 5 and fix it by the original mechanical pressing plate of the device to ensure that the sample is wrinkle-free and without displacement.

[0042] 2. Device parameter setting and calibration: 2.1 Thin Film Thickness Control and Contact State Adjustment: The distance adjustment device 6 is operated through the main control system to control the upper test device 5 to move downward along the slide rail until the upper and lower contact electrodes 8 make slight contact with the surface of the thin film 9 under test; based on the initial thickness recorded in step 1.2, the distance between the upper and lower test devices 5 is finely adjusted with an accuracy of 1 μm / time, and a micrometer is used to assist in measuring the current thickness of the thin film 9 under test until the deviation between the thin film thickness and the initial thickness is ≤ ±1 μm. The distance adjustment device is then locked to avoid the change in thin film thickness during the test from affecting the impedance data.

[0043] 2.2 Setting and Stabilizing Field Environment Parameters: Set the parameters of the field conditioning device 7 according to the test requirements: When a heating field is required, set the target temperature such as 20 ℃, 60 ℃, or 100 ℃, start the heating function, monitor the temperature near the film with a thermometer, and wait for the temperature to stabilize within the range of ±0.2 ℃ of the target value and maintain it for 20 min to ensure thermal equilibrium between the film and the environment, and avoid temperature gradient interference with ion migration impedance. When an electric field is required, set the target electric field strength, such as 0.1 V / cm, 0.5 V / cm, or 1 V / cm, and adjust it according to the sample's voltage withstand characteristics. Apply a constant electric field to the contact electrode 8 and calibrate the actual voltage across the electrode with a voltmeter. The deviation should be ≤ ±0.01V. When a magnetic field is required, set the target magnetic field strength, such as 10 mT, 20 mT, or 40 mT, activate the magnetic field generation function, and use a magnetic field detector to calibrate the magnetic field strength in the thin film area. The deviation should be ≤ ±0.2 mT. After the field parameters stabilize, connect the electrochemical workstation to the contact electrode to begin the impedance testing phase; the specific adjustment parameters are shown in Table 1. Table 1 Adjustment range of different field parameters

[0044] 3. Electrochemical impedance signal acquisition and data calculation: 3.1 Impedance Test Parameter Setting and Signal Acquisition: Set the impedance test parameters on the electrochemical workstation: frequency range 1Hz-10Hz. 6 The Hz frequency range covers the characteristic frequency range of ion conduction. The AC signal amplitude is 10 mV, a small amplitude to avoid polarization damage to the sample. The test mode is a two-electrode system with the upper and lower contact electrodes 8 serving as the working electrode and the counter electrode. When the impedance test is started, the system automatically scans the impedance signal within the set frequency range and generates a Nyquist plot showing the imaginary part vs. the real part of the impedance. During the acquisition process, the field adjustment device parameters are observed in real time. If the field parameters exceed the stable range, such as temperature fluctuations > ±0.2 ℃, the test is immediately paused, and the field parameters are recalibrated before continuing.

[0045] 3.2 Impedance Data Analysis and Ionic Conductivity Calculation: The acquired Nyquist plots were analyzed. An equivalent circuit fitting method using a "resistor-capacitor series" approach was selected to eliminate interfacial capacitance interference, and the bulk resistance R in the through-plane direction of the thin film was extracted. 体 The resistance value corresponding to the intersection of the Nyquist plot and the real axis is the stable value of the real part of the impedance in the low-frequency range; a blank experiment should be performed in advance: under the same contact conditions and field environment without a thin film, impedance tests should be performed according to the parameters in step 3.1, and the contact resistance R should be extracted. 接触 The resistance value obtained by fitting the Nyquist plot is the actual bulk resistance of the thin film, R. 体 =R 拟合 - R 接触 Then, according to the ionic conductivity formula σ = d / (A×R) 体 ), where σ is the ionic conductivity, in mS / cm. -1 d represents the film thickness locked in step 2.1, in cm; S represents the effective area of ​​the contact electrode, in cm², which should be measured and recorded beforehand and substituted into R. 体 R 拟合 Calculate the specific values ​​of , d, and A, and then calculate the through-plane ionic conductivity of the thin film under the current field conditions.

[0046] 4. Repeat testing and result confirmation: 4.1 Repeated testing under the same conditions: Keep the thin film in a fixed state and repeat the impedance test procedure of steps 3.1-3.2 3 times under the same target field environment. Record the ionic conductivity results of the 3 times, calculate the average value as the final test value under the field environment, and ensure that the deviation of the 3 results is ≤ ±8% to ensure the repeatability of the test.

[0047] 4.2 Sample Replacement and Parallel Verification: Replace two thin film samples of the same batch and specifications, and complete the tests according to steps 1.2-4.1 respectively to obtain the average ionic conductivity of different samples under various field environments; if the test results of the three samples deviate by ≤ ±10%, the ionic conductivity test results of the batch of thin films are deemed valid; if the deviation exceeds the range, re-check the electrode cleanliness, impedance fitting method and field parameter stability, and test again after troubleshooting.

[0048] 4.3 Recording and Organizing Results: After the test is completed, record the following parameters: the accuracy of the test device adjustment, field parameters, sample information, initial thickness, drying conditions, impedance test parameters, frequency range, amplitude, Nyquist plot fitting results, and ionic conductivity values. Organize these into a test report to complete the entire test process.

[0049] The following example operation steps are mainly based on the specific implementation of the above test method steps, and the specific modification conditions are described in the examples: As another preferred embodiment of the present invention, see attached... Figure 3 As shown, a 10 μm thin film was placed between the two contact electrodes of the testing device. The micrometer was adjusted to achieve a film compression ratio of 50%, and no external field was applied. The electrochemical workstation was connected to the lead wires of the contact electrodes, and the ionic conductivity of the thin film was tested using electrochemical impedance spectroscopy.

[0050] The test temperature was 25 ℃; the relative humidity was 100%; and the electrochemical impedance spectroscopy test methods were 1 Hz for low frequency and 1,000,000 Hz for high frequency.

[0051] According to the calculation formula σ=d / (A×R) 体 The calculated ionic conductivity is 20 mS / cm. -1 .

[0052] As another preferred embodiment of the present invention, such as Figure 4 As shown, a 10 μm thin film was placed between the two contact electrodes of the testing device. The micrometer was adjusted to make the film compression ratio between 2% and 5%, without applying an external field. The electrochemical workstation was connected to the lead wires of the contact electrodes, and the ionic conductivity of the thin film was tested using electrochemical impedance spectroscopy.

[0053] The test temperature was 25 ℃; the relative humidity was 100%; and the electrochemical impedance spectroscopy test methods were 1 Hz for low frequency and 1,000,000 Hz for high frequency.

[0054] According to the calculation formula σ=d / (A×R) 体 The calculated ionic conductivity is 10 mS / cm. -1 .

[0055] As another preferred embodiment of the present invention, such as Figure 5 As shown, a 10 μm thin film was placed between the two contact electrodes of the testing device. The micrometer was adjusted so that the upper part of the testing device was not in contact with the contact electrodes, and no external field was applied. The electrochemical workstation was connected to the lead wire of the contact electrode, and the ionic conductivity of the thin film was tested using electrochemical impedance spectroscopy.

[0056] The test temperature was 25 ℃; the relative humidity was 100%; and the electrochemical impedance spectroscopy test methods were 1 Hz for low frequency and 1,000,000 Hz for high frequency.

[0057] According to the calculation formula σ=d / (A×R) 体 The calculated ionic conductivity is 8 mS / cm. -1 .

[0058] As another preferred embodiment of the present invention, such as Figure 6As shown, a 1 cm gel was placed between the two contact electrodes of the testing device. The micrometer was adjusted to achieve a film compression ratio of 50%, and no external field was applied. The electrochemical workstation was connected to the lead wires of the contact electrodes, and the ionic conductivity of the film was tested using electrochemical impedance spectroscopy.

[0059] The test temperature was 25 ℃; the relative humidity was 100%; and the electrochemical impedance spectroscopy test methods were 1 Hz for low frequency and 1,000,000 Hz for high frequency.

[0060] According to the calculation formula σ=d / (A×R) 体 The calculated ionic conductivity is 95.7 mS / cm. -1 .

[0061] As another preferred embodiment of the present invention, such as Figure 7 As shown, a 1 cm gel was placed between the two contact electrodes of the testing device. The micrometer was adjusted to make the film compression ratio between 2% and 5%, without applying an external field. The electrochemical workstation was connected to the lead wires of the contact electrodes, and the ionic conductivity of the film was tested using electrochemical impedance spectroscopy.

[0062] The test temperature was 25 ℃; the relative humidity was 100%; and the electrochemical impedance spectroscopy test methods were 1 Hz for low frequency and 1,000,000 Hz for high frequency.

[0063] According to the calculation formula σ=d / (A×R) 体 The calculated ionic conductivity is 82.1 mS / cm. -1 .

[0064] As another preferred embodiment of the present invention, such as Figure 8 As shown, a 1 cm layer of gel was placed between the two contact electrodes of the testing device. The micrometer was adjusted so that the upper part of the testing device was not in contact with the contact electrodes, and no external field was applied. The electrochemical workstation was connected to the lead wire of the contact electrode, and the ionic conductivity of the thin film was tested using electrochemical impedance spectroscopy.

[0065] The test temperature was 25 ℃; the relative humidity was 100%; and the electrochemical impedance spectroscopy test methods were 1 Hz for low frequency and 1,000,000 Hz for high frequency.

[0066] According to the calculation formula σ=d / (A×R) 体 The calculated ionic conductivity is 78.2 mS / cm. -1 .

[0067] In another preferred embodiment of the present invention, as shown in Table 2, a 60 μm thin film is placed between the two contact electrodes of the testing device, and the micrometer is adjusted to make the film compression ratio between 2% and 5%, and a thermal field is applied. An electrochemical workstation is connected to the lead wires of the contact electrodes, and the ionic conductivity of the thin film is tested using electrochemical impedance spectroscopy.

[0068] The test temperatures were 20 ℃, 60 ℃, and 100 ℃; the relative humidity was 100%; and the electrochemical impedance spectroscopy test methods were 1 Hz for low frequency and 1,000,000 Hz for high frequency.

[0069] According to the calculation formula σ=d / (A×R) 体 )Calculate the ionic conductivity as follows: 2 mS cm -1 48 mS cm -1 80 mScm -1 .

[0070] In another preferred embodiment of the present invention, as shown in Table 2, a 60 μm thin film is placed between the two contact electrodes of the testing device, and the micrometer is adjusted to make the film compression ratio between 2% and 5%, and an electric field is applied. The electrochemical workstation is connected to the wires of the contact electrodes, and the ionic conductivity of the thin film is tested using electrochemical impedance spectroscopy.

[0071] The test conditions were as follows: test temperature: 25 ℃; relative humidity: 100%; electric field strength: 0.1 V / cm, 0.5 V / cm, 1 V / cm; electrochemical impedance spectroscopy test method: low frequency 1 Hz, high frequency 1000000 Hz.

[0072] According to the calculation formula σ=d / (A×R) 体 The calculated ionic conductivity is 25 mS / cm. -1 30 mS cm -1 27 mScm -1 .

[0073] Comparison of ion conductivity under different external fields using the testing device of this application Table 2 shows the comparison results of ion conductivity under different external fields.

[0074] In another preferred embodiment of the present invention, as shown in Table 2, a 60 μm thin film is placed between the two contact electrodes of the testing device. The micrometer is adjusted to make the film compression ratio between 2% and 5%, and a magnetic field is applied. The electrochemical workstation is connected to the wires of the contact electrodes, and the ionic conductivity of the thin film is tested using electrochemical impedance spectroscopy.

[0075] The test conditions were as follows: test temperature: 25 ℃; relative humidity: 100%; magnetic field strength: 10mT, 20mT, 40mT; electrochemical impedance spectroscopy test method: low frequency 1 Hz, high frequency 1000000 Hz.

[0076] According to the calculation formula σ=d / (A×R) 体 The calculated ionic conductivity is 18 mS / cm. -120 mS cm -1 21 mScm -1 .

[0077] In this embodiment, the comparison results of ion conductivity at different film compression ratios using the testing device of this application are shown in Table 3: Table 3 shows the comparison of ionic conductivity at different film compression ratios.

[0078] In summary, this invention provides a testing device and method for the through-plane ionic conductivity of thin films, which has the following advantages compared to existing testing methods: This invention can accurately characterize the through-plane ionic conductivity of thin films; it allows for high-precision (1μm) adjustment of the clamping gap, avoiding large measurement errors caused by film deformation during the testing and clamping process; it employs non-destructive clamping measurement, preventing changes in the internal microstructure of the film under pressure or tension, which could lead to distorted test results; conventional thin film ionic conductivity testing is conducted in temperature- and humidity-controlled environments, and there is currently no standardized equipment to test the changes in thin film ionic conductivity under the influence of external fields (magnetic, electric, and thermal). This invention fills the gap in standardized equipment for testing thin film through-plane ionic conductivity under the influence of external fields (magnetic, electric, and thermal); this testing device can apply one or more combinations of electric, magnetic, and thermal fields across the film in situ to study the changes in ionic conductivity of the film under the influence of external fields; the sandwich electrode structure allows for easy replacement of the field emission source without affecting the thickness and structural dimensions of the clamp; the entire device has a simple and reasonable structure, is easy to operate, and can significantly improve testing efficiency.

[0079] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A device for testing thin film through-plane direction ion conductivity, characterized by, The utility model relates to a kind of thin film testing device, including: Base (1) and testing device (5); The base (1) is vertically provided with support frame (2); Distance adjusting device (6) is arranged on the support frame (2) and can slide up and down in vertical direction, and the distance adjusting device (6) is used for fine adjustment to the clamping gap of the film (9) to be measured; The testing device includes first test unit (5-1) and second test unit (5-2); The first test unit (5-1) is arranged at the bottom of the distance adjusting device (6); The second test unit (5-2) is arranged on the top surface of the base (1); Contact electrode (8) is arranged on the first test unit (5-1) and the second test unit (5-2), for contacting the film (9) to be measured; Cavity is opened in the first test unit (5-1) and the second test unit (5-2), and field adjusting device (7) is respectively inserted in the cavity, and the field adjusting device (7) is used for accessing and adjusting different electric field, magnetic field or thermal field.

2. The device for testing the Through-Plane ion conductivity of a thin film according to claim 1, wherein, Slide rail (3) is opened in the support frame (2); The distance adjusting device (6) is movably connected to the slide rail (3) through connecting device (4).

3. The device for testing the Through-Plane ion conductivity of a thin film according to claim 2, wherein, The connecting device (4) includes horizontally arranged fixed plate (4-1), and the fixed plate (4-1) is connected to the slide rail (3) through fastening screw (4-2); The distance adjusting device (6) includes size adjusting part (6-1) and fixing part (6-2) connected to each other; The top of the fixing part (6-2) is connected to the size adjusting part (6-1), the middle part is connected to the fixed plate (4-1), and the bottom is connected to the first test unit (5-1).

4. The device for testing the Through-Plane direction ion conductivity of a thin film according to claim 3, wherein, Scale is arranged on the support frame (2), and the fastening screw (4-2) can indicate the adjustment scale position to realize the coarse distance adjustment of the testing device (5), wherein the adjustment range of the coarse distance adjustment is 0 cm~20 cm. Micrometer, vernier caliper or electronic ruler is arranged on the size adjusting part (6-1) to realize the fine distance adjustment of the testing device (5), wherein the adjustment range of the fine distance adjustment is 0 mm~20 mm, and the adjustment accuracy is 1 μm.

5. The device for testing the Through-Plane ion conductivity of a thin film according to claim 1, wherein, Thermally conductive insulating material is coated in the cavity, and the thermally conductive insulating material is ceramic material, hexagonal boron nitride or high polymer material; The contact electrode (8) is made of metal electrode material or two-dimensional material.

6. The device for testing the Through-Plane direction ion conductivity of a thin film according to claim 1, wherein, The field adjusting device (7) is connected to direct-current stabilized power supply and voltage dividing circuit to adjust electric field, and the adjustment range is 0.01 V / cm~10 V / cm; Alternatively, the field adjusting device (7) is connected to electromagnet and current adjusting module to adjust magnetic field, and the adjustment range is 0 mT~200 mT; Alternatively, the field adjusting device (7) is connected to semiconductor temperature control module and platinum resistance temperature measurement feedback adjustment module to adjust thermal field, and the adjustment range is-40 ℃~200 ℃.

7. The device for testing the Through-Plane ion conductivity of a thin film according to claim 1, wherein Wherein: When the field adjusting device (7) is connected to electric field, the field adjusting device (7) is made of platinum-iridium alloy, and the surface is plated with titanium nitride conductive layer. The field adjusting device (7) is connected with a magnetic field, and the field adjusting device (7) is made of a neodymium-iron-boron permanent magnet and wrapped with a silicon steel sheet magnetic shielding layer on the outside; The field adjusting device (7) is connected with a thermal field, and the field adjusting device (7) is made of a composite structure of an aluminum nitride ceramic substrate and a nickel-chromium heating sheet, and the surface of the ceramic substrate is covered with a polytetrafluoroethylene thermal insulation layer.

8. A method for testing the Through-Plane ion conductivity of a thin film, based on the device for testing the Through-Plane ion conductivity of a thin film according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: Placing the pretreated test film (9) on the second test unit (5-2); Driving the first test unit (5-1) to move downward by the distance adjusting device (6) until the contact electrodes (8) of the first test unit (5-1) and the second test unit (5-2) form a rigid contact state with the test film (9); Adjusting the distance adjusting device (6) to fine-tune the distance between the first test unit (5-1) and the second test unit (5-2) with micron-level precision until the current thickness of the test film (9) deviates from the initial thickness by ≤ ±1 μm; Setting the parameters of the field adjusting device (7) according to the test requirements to access and adjust different electric fields, magnetic fields or thermal fields to construct a field environment; In the current field environment, collecting electrochemical impedance signals and calculating the Through-Plane direction ion conductivity of the film according to the electrochemical impedance signals.

9. The method of claim 8, wherein the thin film is a polymer electrolyte membrane. The pretreatment process of the test film (9) comprises: Measuring the thickness of the test film (9) at multiple uniformly distributed regions with a micrometer with micron-level precision and taking the average value as the initial thickness; Cutting the test film (9) into a shape matching the contact electrode (8); If the test film (9) is an electrolyte film, the electrolyte film is pre-dried.

10. The method of claim 8, wherein the thin film is a polymer electrolyte membrane. The method for collecting electrochemical impedance signals in the current field environment and calculating the Through-Plane direction ion conductivity of the film according to the electrochemical impedance signals comprises: Collecting electrochemical impedance signals in a preset frequency range; Generating a Nyquist plot according to the electrochemical impedance signals; Performing equivalent circuit fitting on the Nyquist plot to extract the bulk resistance of the film in the Through-Plane direction, combining the contact resistance obtained from a blank experiment to calculate the actual bulk resistance of the film; Based on the actual bulk resistance of the film, the thickness of the film during the test and the effective area of the contact electrode, the Through-Plane direction ion conductivity of the film is calculated according to the ion conductivity formula.

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